Rust 1.54.0 lints (#2483)

## Issue Addressed

N/A

## Proposed Changes

- Removing a bunch of unnecessary references
- Updated `Error::VariantError` to `Error::Variant`
- There were additional enum variant lints that I ignored, because I thought our variant names were fine
- removed `MonitoredValidator`'s `pubkey` field, because I couldn't find it used anywhere. It looks like we just use the string version of the pubkey (the `id` field) if there is no index

## Additional Info



Co-authored-by: realbigsean <seananderson33@gmail.com>

crypto/bls/src/generic_aggregate_signature.rs

@@ -221,7 +221,7 @@ where
 {
     fn from(sig: &GenericSignature<Pub, Sig>) -> Self {
         let mut agg = Self::infinity();
-        agg.add_assign(&sig);
+        agg.add_assign(sig);
         agg
     }
 }